1. Field of the Invention
The present invention relates to fused disconnect devices for electrical power distribution systems, and in particular, for low voltage, high current telecommunications applications.
2. Related Art
U.S. Pat. No. 5,355,274 discloses a fused disconnect device 100. The disclosed device includes a housing 130, 730 and a fuse holder 400, 702 which is insertable into the housing. In the disclosed device, the fuse is retained within the fuse holder 400, 702 by electrical contacts 410, 414, 706, 708 that make electrical contact with the fuse, and which mechanically secure the fuse within the fuse holder 400, 702. The electrical contacts of the fuse carrier 400, 702 then engage with electrical contacts 178, 180, 744, 746 within the main body 130, 730.
Thus, there are two sets of contacts. A first set of contacts is secured within the fuse carrier, and which is used to make electrical contact with the fuse. The first set of contacts are also frequently used to secure the fuse within the fuse carrier. A second set of electrical contacts is included in the main body, and is used to make electrical contact with the first set of contacts in the fuse holder. The use of two sets of electrical contacts creates inefficiencies in materials, as well as in the conduction of electric current. Specifically, a connection is required between the fuse contacts and the first set of contacts, and a second connection is required between the first set of contacts and the second set of contacts. Each connection creates potential electrical inefficiencies.
In addition, as can be seen from FIGS. 8 and 19 of the '274 patent, it is difficult to insert the fuse into the contacts of the fuse holder because the contacts of the fuse holder must strongly embrace the contacts of the fuse in order to make a satisfactory electrical connection. In many applications, particularly high current applications, the tight fit between the fuse contacts and the contacts with the fused device make it difficult to install the fuse in the disconnect device.
The disclosed fused disconnect device also includes an alarm fuse 516 that is located at a longitudinal end of the fuse. See, e.g., FIG. 1. Placing the alarm fuse at the longitudinal end of the fuse results in an unnecessarily long main body 130. In addition, the wiring of the alarm fuse is difficult from this position.